1. Field of the Invention
The present invention relates to a method for automatic timed deletion of video and audio streams stored in a recording medium such as a rewritable optical disc.
2. Description of the Related Art
Recently, in accordance with rapid advancement of standardization of a novel high density rewritable recording medium such as ‘Blu-ray Disc Rewritable’(hereinafter referred to as BD-RW) where high quality video and audio data can be recorded for many hours, it is expected that related products will soon be developed and released to consumer market.
FIG. 1 illustrates a partial structure of an optical disc apparatus such as a video disc recorder (VDR) which records signals in a recording medium such as BD-RW or plays signals thereof. The optical disc apparatus may comprise an optical pickup 2 to read out recorded signals from the recording medium such as BD-RW 1 or to record processed data streams from external inputs; a VDR system 3 to process signals read out from the optical pickup 2 for playback or to transform external data streams into those suitable for recording; and an encoder 4 to encode analog signals from external sources to output to the VDR system 3.
As illustrated in FIG. 2, clips of A/V streams recorded in the BD-RW 1, for example, a first clip of A/V stream (Clip 1 A/V Stream) and a second clip of A/V stream (Clip 2 A/V Stream), each of which is recorded consecutively are managed by a first real playlist (Real PlayList 1) and a second real playlist (Real PlayList 2) generated automatically at the time of recording respective A/V streams, wherein respective play control information to read out and play are contained.
In addition, a playlist enabling access to sections selectively chosen from a part or whole of the A/V stream clips recorded in said manner can be generated, which is termed as a virtual playlist. Referring to FIG. 2, within the virtual playlist, a playitem of main path (PlayItem) to read out and play the first clip of A/V stream associated with the first real playlist and a sub playitem of a subpath (Sub PlayItem) to read out and play the second clip of A/V stream associated with the second real playlist can be recorded and managed.
Accordingly, while performing a series of play operations of reading out and playing the first clip of A/V stream managed by the first real playlist, the optical disc apparatus of VDR system 3 can select and play the second clip of A/V stream managed by the second real playlist upon user request.
On the other hand, the VDR system 3, in response to user request, may delete or edit a part of the first clip of A/V stream or second clip of A/V stream. As depicted in FIG. 3, in case a part of the second clip of A/V stream is deleted, the remaining part of the partially deleted A/V stream is broken up into an A/V stream of second clip and an A/V stream of third clip with corresponding second real playlist and third real playlist generated and further managed, wherein play control information to read out and play the A/V streams are incorporated.
In order to allow a user to randomly select, edit and play real playlists managed by said procedure, a virtual playlist is generated and recorded, wherein the playitem of the main path to read out and play the A/V stream of first clip associated with the first real playlist and sub playitem of the sub path to read out and play the A/V stream of third clip associated with the third real playlist can be recorded and managed at the same time. Consequently, in response to user request, the VDR system 3 of the optical disc apparatus, while performing a series of play operations of reading out and playing the A/V stream of the first clip associated with the first real playlist, can select and play the A/V stream of the third clip associated with the third real playlist.
Because the optical disc apparatus as described, in response to user request, allows random editing of recorded clips of A/V streams and playing clips of the A/V streams, however, user's unlimited playback or illegal editing of proprietary television programs or movies are made possible, where copyright protection and payment are essential. Presently, however, an effective means to prohibit such behavior is yet to be prepared.